It is important in producing displays or prints from digital images to fit the dynamic range of the originally captured scene to the dynamic range of the materials available for displaying or printing using the best possible transform. A limiting factor is the dynamic range of the materials available for displaying or printing. By selectively choosing the proper transform for displaying or printing, it is possible to display or print esthetically pleasing images on materials that have less dynamic range than the original scene.
As new materials such as thermal print media and receivers and ink jet technologies have become available for displaying or printing, they have introduced larger dynamic range than available with previous technologies. It is well known how to display or print digital images on these types of media. However, it is difficult to design different transforms that best take advantage of these new media. A key element in any new transform is to be able to utilize the full dynamic range of the media for displaying or printing the digital images.
There have been a number of techniques for improving the tone reproduction of digital images, see for example, U.S. Pat. No. 4,792,518 and U.S. Pat. No. 5,300,381. For a discussion of tone reproduction, see "The Tone Reproduction of Colour Photographic Materials," R. W. G. Hunt, I. T. Pitt, and P. C. Ward, J. Photog. Sci., 17:198 (1969).
As set forth in the above disclosures, a number of techniques are disclosed which require that the media be photographic media and the techniques for making the images are very complex. The publication by Hunt et al. describes the "ideal system" for printing photographic images to correct for camera flare, printer flare, and viewing flare but offers no practical way to implement this theoretical tone reproduction curve because of the lack of digital imaging tools and the limitations of the materials available in 1969.
U.S. Pat. No. 5,528,339 discloses techniques for improving the tone reproduction of digital images on other media such as thermal, ink jet and electrophotographic. However, the media available for the printing of the digital images far exceeds the dynamic range previously described by having lower minimum densities and considerably higher maximum densities. The same problems exist for soft copy outputs on screens.